Firstly let me just say that if a friend sends you a warning email, "this is not joke" "pass this on to all you friends" etc. etc. 99 out of a hundred are hoaxes,or a virus or worm themselves. (Check by using www.hoax-slayer.com)
Never ever send them on by using the forward button. It too late for you, whoever started the hoax already has your email address, just look at the size of the address list that has your name on it.
If you wish to send it (I wouldn't) copy the content and paste into a new email.
¿Well how can you protect yourselves from the nasties listed below?

• Keep your Virus software updated and run a full scan regularly (1/52)
  
• Make sure your firewall is on it's part of the control panel (in Windows 10 right click the start button to find it
• Make use of windows defender (anti-spyware) anti- virus-anti-malware
   

Beware of are sites offering free system error scans / free online spyware scans, they themselves usually infect you with just that. Listed below in my order of preference
are free Anti-Virus programs
www.avast.com/eng/download-avast-home.html
Or if you prefer AVG version 8 is available now here
free.avg.com/ww.download-avg-anti-virus-free-edition#
A great free firewall is available from this link www.personalfirewall.comodo.com/
It's very similar to ZoneAlarm® but doesn't keep asking you to pay.
A very good and free anti-spyware programe can be found here
www.superantispyware.com/download.html
A test of your firewall and vulnerable ports can be done by
www.hackerguardian.com/sas/user/free/new_user_registration.jsp

If you do want an online scan the links from Google should be kosher.

The most common blunder people make when the topic of a computer virus arises is to refer to a worm or Trojan horse as a virus. While the words Trojan, worm and virus are often used interchangeably, they are not the same. Viruses, worms and Trojan Horses are all malicious programs that can cause damage to your computer, but there are differences among the three, and knowing those differences can help you to better protect your computer from their often damaging effects.

A computer virus attaches itself to a program or file so it can spread from one computer to another, leaving infections as it travels. Much like human viruses, computer viruses can range in severity: Some viruses cause only mildly annoying effects while others can damage your hardware, software or files. Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it cannot infect your computer unless you run or open the malicious program. It is important to note that a virus cannot be spread without a human action, (such as running an infected program) to keep it going. People continue the spread of a computer virus, mostly unknowingly, by sharing infecting files or sending e-mails with viruses as attachments in the e-mail.

A worm is similar to a virus by its design, and is considered to be a sub-class of a virus. Worms spread from computer to computer, but unlike a virus, it has the capability to travel without any help from a person. A worm takes advantage of file or information transport features on your system, which allows it to travel unaided. The biggest danger with a worm is its capability to replicate itself on your system, so rather than your computer sending out a single worm, it could send out hundreds or thousands of copies of itself, creating a huge devastating effect. One example would be for a worm to send a copy of itself to everyone listed in your e-mail address book. Then, the worm replicates and sends itself out to everyone listed in each of the receiver's address book, and the manifest continues on down the line. Due to the copying nature of a worm and its capability to travel across networks the end result in most cases is that the worm consumes too much system memory (or network bandwidth), causing Web servers, network servers and individual computers to stop responding. In more recent worm attacks such as the much-talked-about .Blaster Worm., the worm has been designed to tunnel into your system and allow malicious users to control your computer remotely.

A Trojan Horse is full of as much trickery as the mythological Trojan Horse it was named after. The Trojan Horse, at first glance will appear to be useful software but will actually do damage once installed or run on your computer. Those on the receiving end of a Trojan Horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source. When a Trojan is activated on your computer, the results can vary. Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system. Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.